An API is a source code interface that a computer system or program library provides in order to support requests for services from a software application. An API is specified in terms of a programming language that can be interpretative or compiled when an application is built, rather than an explicit low level description of how data is laid out in memory. The software that provides the functionality described by an API is said to be an implementation of the API.
Various devices such as electronic devices, computing systems, portable devices, and handheld devices have software applications. The API interfaces between the software applications and user interface software to provide a user of the device with certain features and operations. A user may desire certain operations such as scrolling, selecting, gesturing, and animating operations for a display of the device.
Scrolling is the act of sliding a directional (e.g., horizontal or vertical) presentation of content, such as text, drawings, or images, across a screen or display window. In a typical graphical user interface, scrolling is done with the help of a scrollbar or using keyboard shortcuts, often the arrow keys. Gesturing is a type of user input with two or more input points. Animating operations include changing content within a given time period.
The various types of devices may have a limited display size, user interface, software, API interface and/or processing capability which limits the ease of use of the devices. User interfaces of devices implement APIs in order to provide requested functionality and features. These user interfaces can have difficulty interpreting the various types of user inputs and providing the intended functionality associated with the user inputs.